Caption: MODEL RELEASED: Radiocarbon dating. Samples of bone being digested in inorganic solvents, prior to being radiocarbon dated. Only the amino acids in the bone are used in the technique, which measures the ratio between the radioactive isotope carbon-14 (14C) and the stable carbon-12 (12C) isotope in a sample. The ratio of 14C to 12C may be related to the time since the death of the animal or plant being investigated. Convention states that 14C has a half-life of 5568 years (+/- 30 years), although this is now thought to be too short. Dates from the process are given either as radiocarbon dates, or as solar dates after various corrections have been made.